* Battery light comes on: This is the most common and obvious sign. A constantly illuminated or flickering battery light indicates the alternator isn't charging the battery properly.
* Dim headlights and other electrical issues: If your headlights dim significantly when the engine is running, or other electrical components (like the radio or power windows) are acting strangely, the alternator might be failing.
* Battery consistently needs jump-starting: If your battery constantly needs a jump start, even after it's been charged, the alternator is likely the culprit.
* Whining or squealing noise: A high-pitched whine or squeal coming from the alternator area, especially at higher engine speeds, can be a sign of failing bearings or other internal issues.
* Age: While not a definitive indicator, an alternator that's 10+ years old (or even older, given the age of your Silverado) is more prone to failure and should be monitored closely. However, proper maintenance can extend an alternator's life significantly.
* Visual inspection: If you're comfortable with basic car maintenance, visually inspect the alternator for signs of damage, corrosion, loose connections, or leaks. However, this is often not enough to determine internal issues.
Instead of a specific mileage or timeframe, focus on these symptoms. If you experience any of the above, it's best to have your alternator tested by a mechanic or auto parts store. They can perform a load test to determine its charging capacity and whether replacement is necessary. Ignoring a failing alternator can leave you stranded with a dead battery.
